1. Field of the Invention
The present invention generally relates to camera lens modules and, more particularly, to a zoom camera lens module.
2. Discussion of the Related Art
With the rapid development of multimedia technology, digital devices such as digital still cameras (“still cameras”) and digital video cameras (“video cameras”) have become wide-spread in many countries in recent years. Consumers expect such still cameras and video cameras to have a compact size, while still being capable of providing high imaging quality. Similar to film-based cameras, the ability to zoom is a considered to be a necessary function for achieving high image quality over a variety of imaging distances. Generally, there are two kinds of zoom methods, an optical zoom and a digital zoom. Imaging quality tends to relatively poor when digital zooming is relied upon, while imaging quality is generally nicer when using an optical zoom. In order to satisfy a market demand, camera lens of digital cameras should have an optical zoom function.
One kind of camera lens is disclosed in U.S. Pat. No. 4,291,958, the contents of which are hereby incorporated by reference thereto. The camera lens includes a fixed barrel, a movable barrel, two links, and two bender elements. The fixed barrel and the movable barrel each has a lens group therein and are coaxial. The bender elements are of cantilever fashion and are made of piezoelectric materials. One end of each bender element is fixed to an electric device and connected to a power supply. Another end of each bender element is connected to one link. The bender elements are approximately parallel to an axis of the two barrels. The links connect the bender elements and the movable barrel. In an original state (i.e. the when the power supply does not supply electricity), one bender element and one corresponding link forms an angle smaller than 90° therebetween. When the power supply supplies electricity to the bender elements, the bender elements deform under the effect of piezoelectricity. It results that the angle between the elements and the links changes, and the movable barrel thereby moves. Thus, the camera lens zooms or focuses.
However, the size of the bender elements and links are so large that the camera lens unit, as a whole, is fairly big. Therefore, digital cameras with such camera lens will be very large, and consumers cannot be expected to enjoy these bulky digital devices. In addition, the bender elements and links are very long, so a rigidity of the camera lens is less than optimal. Thus, the camera lens can be unsteady, which can lead to bad imaging.
What is needed, therefore, is a camera lens module having optical zoom function that has a small size and nice rigidity.